Amendments to Articles of Incorporation or Bylaws; Change in Fiscal Year.

(a) On September 27, 2012, the Board of Directors of Alcoa Inc. (Alcoa) approved amendments to Alcoas By-Laws, effective as of that date. The amendments amend and update certain
sections of Article III of the By-Laws relating to board meetings. The amendments:

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clarify in Article III, Section 4 that the annual meeting of the board may take place on such day or at such time or place as the board may
determine;

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update Article III, Section 7 by providing that notices for meetings of the board may be given by email or other electronic communication means;

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provide in Article III, Section 8 that board and committee action may be taken by unanimous consent, which may be given in writing or transmitted
by fax, e-mail or similar electronic means; and

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clarify in Article III, Section 16 that director participation in meetings remotely may occur by means of electronic technology.

The foregoing summary of the amendments to Alcoas By-Laws is qualified in its entirety by reference
to the full text of the amended By-Laws attached hereto as Exhibit 3 and incorporated herein by reference.

Item 8.01.

Other Events.

On
October 1, 2012, Alcoa issued a press release confirming that the U.S. Environmental Protection Agency (EPA) has released the Proposed Remedial Action Plan (PRAP) for the Grasse River. As a result of the EPAs
issuance of the PRAP, Alcoa expects to record an associated after-tax charge of approximately $85 million, or $0.08 per share, in its results for the third quarter of 2012. A copy of the press release is attached hereto as Exhibit 99 and is
incorporated herein by reference.

Item 9.01.

Financial Statements and Exhibits.

(d)

Exhibits.

The following are
filed as exhibits to this report:

3

By-Laws of Alcoa Inc., as amended effective September 27, 2012.

99

Alcoa Inc. press release dated October 1, 2012.

2

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the Registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.